C# - Detecting device on serial port hangs if no device exists

Question

So, I am building an app that has to detect whether a device is connected or not to a random serial port before continuing. Although the device connects via USB, it is listed as COMPORT (COM5 in my case, but it depends on the PC). I have the following code which does work if the device is plugged in, no problem, goes as normal in just one second, but if a device matching the name I am looking for is not connected, the application does nothing, when it should show up the messagebox saying no device is attached. Help would be appreciated.

ManagementScope connectionScope = new ManagementScope();
SelectQuery serialQuery = new SelectQuery("SELECT * FROM Win32_SerialPort");
ManagementObjectSearcher searcher = new ManagementObjectSearcher(connectionScope, serialQuery);
try
{
  foreach (ManagementObject item in searcher.Get())
  {
    string desc = item["Description"].ToString();
    string deviceId = item["DeviceID"].ToString();
    if (desc.Contains("Arduino"))
    {
      device_loc = deviceId;
      serializer.RunWorkerAsync();
      BeginInvoke((MethodInvoker)delegate
      {
         next_step.Enabled = true;
      });
    }
    else
    {
      MessageBox.Show("Could not detect any Arduino device connected, please connect your device.",
        "No device", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
      BeginInvoke((MethodInvoker)delegate
      {
          next_step.Text = "Ok, let's continue.";
          next_step.Enabled = true;
      });
    }
  }
}
catch (ManagementException xe)
{
  MessageBox.Show("Could not check for serial devices due to the following error: " + xe, 
    "Ooops", MessageBoxButtons.OK, MessageBoxIcon.Error);
}

The above code runs in a separate backgroundworker component. As I said, if the device is connected, it does work, if the device is not, I never get to the point where the messagebox saying it is not shows.

Answer 1

You should complete foreach cycle before showing "Not detected any Arduino device". You may use flag variable for this. Please try this code:

bool arduinoFound = false;
foreach (ManagementObject item in searcher.Get())
{
    string desc = item["Description"].ToString();
    if (desc.Contains("Arduino"))
    {
        arduinoFound = true;
    }
}

if (!arduinoFound)
    MessageBox.Show("Could not detect any Arduino device connected");